The invention relates to an occupant protection device for motor vehicles.
The side windows of a vehicle provide a hazardous potential for the occupant or individual parts of the occupant's body being flung out of the vehicle should the vehicle overturn. U.S. Pat. No. 6,312,009 B1 (incorporated by reference herein) discloses a head airbag system, in which an airbag is shortened along its lower edge and is thereby tensioned between two fastening points, thus reducing the risk of an occupant being flung out.
DE 100 21 577 A1 and DE 199 26 269 A1 (both documents are incorporated by reference herein in their entireity) disclose protection devices for the head and shoulder region of vehicle occupants, in which tightening of an unfolded airbag, in particular along its lower edge, is brought about via a flexible strap or a tightening string. A similar prior art is also described in the publications DE 101 29 581 A1, DE 199 22 994 A1 and DE 196 54 490 A1 (all three documents are incorporated by reference herein in their entireity).
The concepts known in the prior art have the aim of bringing an airbag under tension after it has unfolded or at least fixing it in place. Since an airbag has an elastic behaviour on account of its chambers, the known clamping systems disadvantageously have to realize a high amount of pretension in order to compensate for the elastic behaviour of the airbag. In particular, the airbag is to be prevented from being able to push outwards in the region of a window. In this situation, there is the risk of a vehicle occupant being flung out of the vehicle.
There is therefore a need for reliable, simple solutions for fitting an airbag or in general a protection element in the vehicle in such a manner that it reliably prevents a vehicle occupant from being flung out of the vehicle.